Introduction: It is generally assumed that dialysis patients (DP) have a more severe bleeding diathesis related to platelet dysfunction than pre-emptively transplanted patients (PEP) who are not yet on dialysis. Therefore, in many centers, PEP receive heparin, with the aim to prevent graft thrombosis, whereas DP do not. However, a solid biochemical basis for this difference is lacking.

M&M: Twenty-eight recipients were PEP and 28 were DP. Living kidney donors were included as a control group. PEP were given 5000 IU of heparin prior to reperfusion. Blood samples were taken at incision, and two hours after skin closure. Five minutes after reperfusion, blood samples were taken from the renal vein and systemic circulation. The following hemostatic and fibrinolytic parameters were analysed: Platelet factor 4 (PF4) as a specific platelet activation marker, prothrombin fragment 1+2 (F1+2) for coagulation activation and D-dimer for clot breakdown. Plasma hemostatic and fibrinolytic potential was studied by thrombin generation (TGA) and clot lysis time (CLT) assays.

Results: At start of surgery, both DP and PEP showed activation of platelets and coagulation as evidenced by elevated levels of PF4, F1+2, and D-dimer compared to living donors. In addition, both DP and PEP showed a decreased plasma fibrinolytic potential on CLT assays. The pre-transplantation hemostatic status of both DP and PEP was remarkably similar. Five minutes after reperfusion there was much more pronounced platelet activation, without concomitant coagulation activation in DP compared to PEP. This was corroborated by a substantial increase in PF4 in DP. Two hours post-surgery activation of platelets (PF4), coagulation (F1+2, D-dimer), and plasma coagulatory potential (TGA) were substantially higher in DP compared to PEP. At that time, DP also displayed a more pronounced hypofibrinolytic state compared to PEP.

Discussion: Prior to kidney transplantation, DP and PEP have a comparable hemostatic state. Post transplantation, DP show a more pronounced activation of coagulation and inhibition of fibrinolysis, presumably related to the heparinisation of PEP. These results strongly contrast with the general belief that DP have an increased bleeding risk. Our results suggest that many centers erroneously withhold DP from adequate peri-operative anticoagulation during transplantation.